The amount of current flowing through an electrical cable is an important value to know for the use of a cable and for the operation of devices connected to it. On one hand, from the measured value the power transmitted through the cable can be closed, and on the other hand, such a measurement fulfills a safety aspect. Thus, power limits, the surpassing of which could, for example, overload the cable or the device connected to the cable, can be monitored by means of the current measuring transducer. The cable cross-sectional area and assembly determine the acceptable power capacity of the cable.
Current measurements as such are known for a cable through which an electrical current flows. For an example of such, patent document DE 689 09 847 T2 gives an electrical measuring transducer with a coil that is arranged around the electrical conductor wherein the conductor is guided centrally through the coil.
Mainly, current measuring methods for an electrical cable can be distinguished into those measuring methods that require an electrical measuring element in the electrical conductor and those methods that infer the electrical current flowing through the electrical cable from an electrical or magnetic field surrounding an electrical conductor. Such an element that, for example, is inserted into the electrical conductor is a shunt resistor.
Measuring methods that manage without such an inserted element, on the other hand, measure inductively.
Current measuring transducers, as are known in prior art, are typically pushed onto the electrical cable. In this way, an inductive element encloses the electrical cable and enables a measurement by means of the current measuring transducer. The precise placement of a prior art current measuring transducer on the desired location proves to be difficult. A subsequent placement on an existing, already laid cable, or the simple exchange of a current measuring transducer, moreover, is typically not possible.
Existing solutions in order to enable a subsequent placement of a current measuring transducer on an electrical cable do not have a circularly closed ring that is arranged around the electrical cable in a ring-shaped manner. Also, the introduction of the electrical cable into the device becomes difficult.